Vehicle Building 101

Root Prim

In Second Life, the root prim is the last prim linked into an object, it is the prim that glows yellow in Edit mode.
In a vehicle it is the prim from which the scripts drive/turn from and its alignment determines the forward direction of the vehicle.

When you select your entire vehicle and set it to zero rotation in the object tab, it should be level and pointed east. If not you will need to unlink just the root prim, turn and level the vehcile and link it back in.

A non-sculpted invisible prim is strongly recommended for the root as you can move it around within the build and you are not stuck building around the alignment of an existing part.

To make a prim invisible, select just that prim using Edit Linked Parts, then select texture and in the texture search window select Default Transparent.

Root prims should not be tiny because they will have less physical torque against the rest of the build, and your steering will suffer.

Root prims should not lay flat on the ground in bikes or they will negatively impact banking.

Your root should be centered to the frame and wheels! Its height will affect banking and its position forward/backward will affect steering. If your root prim is not centered, your steering will be out of alignment.

When your vehicle is at zero rotation, your wheels should be level. If they are the same radius, they should have the same height coordinate.

For mesh builders, a non-mesh root prim cube is also a good idea. Your root prim shape when using mesh is always convex hull, and will use up more of your physics allotment faster if it is a complex mesh or sculpted object.

Animation Bounding Box

Animations have an invisible bounding box that can interfere with the ground and cause vehicles to lift if the hip height of the pose is not low enough for the vehicle.

If your vehicle lifts up when you sit you will need to change animations, or make the vehicle larger to lift the animation higher from the ground.

If you make your own animations, you want the hip height of the animation to be at ground sit height or even lower. -2.0m is usually perfect.

See this video for more explanation: Avoiding problems with Second Life vehicle poses

Editing Scripts

The scripts are designed to be plug-and-play as much as possible, but ultimately you will want to adjust them to fine tune them for your specific vehicle.
Every vehicle will respond differently due to its physical mass and root placement, what parts are touching the ground, etc.

The vehicle is only as slow/fast as you set it. You will need to adjust your gear power to compensate for the size of your vehicle.

Don't be afraid to play with the values at the top of the scripts, it is recommended that you adjust the steering and gear power for the size of your vehicle.
A smaller vehicle must have less steering power or it will be impossible to control. A large vehicle my need more steering power to compensate for its mass. The same goes for your gear power.

See customizing, steering and physics


To set permissions on individual scripts, open the vehicle, right click on the script and make sure Modify and Transfer/Resell are unchecked and Copy is checked.
When you distribute a vehicle you should always give Copy permissions, as vehicles can be lost on region crossings etc, and your bike owner should be able to rez a new one.

If you have acquired any bike parts, chances are they are not allowed to be given away full perms, so always double check that any bike you make and distribute is set to No Transfer.


To get the UUID key for your texture, right click it in your inventory and select Copy Asset UUID and then paste it into the notecard or script. You must have full permissions on a texture or sound in your inventory to be able to copy the UUID key. Note that unlike sounds and textures, animations/poses cannot be called by uuid in a script, they must be called by name and present in the prim.

Mesh & High Prim Linksets